An Organic Light-Emitting Diode (OLED) display panel is one of focuses in the field of display panels at present, and as compared with a Liquid Crystal Display (LCD), the OLED display panel has low power consumption, a low production cost, self-light-emission, a wide angle of view, a high response speed, and other advantages. At present, the OLED display panel has come to take the place of the traditional LCD display panel in the field of mobile phone displays.
Unlike the LCD in which brightness is controlled using stable voltage, the OLED display which is current-driven, needs to be controlled using stable current to emit light. Typically the OLED display is driven by a drive transistor in a pixel driver circuit in the OLED display, where while the drive transistor is operating, there is some defect in the drive transistor, and the drive transistor keeps on operating nearly all the time, so the source of the drive transistor may be biased at the same voltage for a long period of time, and thus the threshold voltage thereof may drift, and the mobility thereof may vary by an increasing factor, thus making the characteristic of the drive transistor drift, which may result in a display abnormality, and thus degrade the stability of the display.
Accordingly in the OLED display panel, typically a pixel circuit in which the threshold voltage Vth of the drive transistor is compensated for is used to drive the OLED to emit light. In order to compensate for the threshold voltage, the pixel circuit is typically 7T1C-structured (including seven switch transistors and one capacitor) as illustrated in the circuit structure of FIG. 1A, and the corresponding timing diagram of FIG. 1B, where two reset signal lines are needed to provide voltage signals loaded on an initialized signal terminal VINT and a reference signal terminal VREF. Since the Pixels Per Inch (PPI) of the display has been improved to 600+ at present, the limit of the array process for the sophisticated pixel circuit has been challenged. Particularly in a Virtual Reality (VR) display, or another product for which a high PPI (typically higher than that required for a Quarter High Definition (QHD) display) is required, signal lines in the existing OLED display panel are so complicated that it may hinder the high PPI from being achieved.